Contact List

I need to setup a shared contact list. What I would like is whenever a email goes to all@ourdomain.com it gets forwarded to everyone on the list. The majority of our users are using squirrelmail and, its a long story, don't have access to the LDAP plugin. I've looked into to Mailman but its a lot more complicated then I need (and as much as I played with the settings couldn't figure out how to keep people from being able to subscribe). I could use the forwarding option but the list is 75-85 email addresses and would be a pain to manage that way. Any suggestions?